Female preying mantises f east on their male lovers after sex red-sided garter snakes mate with multiple partners simultaneously. For most organisms, mating is purely a reproductive strategy to pass on their genetic material to their progeny in the case of many species, such as voles, even monogamy comes with an evolutionary advantage.īut no animal represents the sentiment of Valentine's Day more than the lovebird. In the animal kingdom, though, relationships don't often fit with conventional human ideas of love. Humans around the globe will express their love today through chocolate, greeting cards, and a cacophony of stuffed animals.